Uterine infections in the postpartum cow: I. Effect of dietary crude protein restriction

The relationship between adequate (0.96 kg per head daily) and deficient (0.32 kg per head daily) intake of crude protein between 150 days prepartum and 110 days postpartum and the incidence of postpartum infections in the bovine uterus was studied. The incidence of infection at 25 days postpartum was 52.2% and 48.1% (P > .10) for cows in the protein adequate and protein deficient groups, respectively. However, at 40 days postpartum, 21.7% of cows in the protein adequate group had infections $\text{vs}$ 51.9% (P < .05) of cows in the protein deficient group. In addition, the incidence of infection within the protein adequate group between sampling times was different (P < .10); whereas, the incidence within the protein deficient group between sampling times was not different (P > .10). Eighty-three bacterial isolates representing 27 species were recovered from the total of 100 samples. $\text{Corynebacterium}$$\text{pyogenes}$ and $\text{Fusobacterium}$$\text{necrophorum}$ were the most frequently isolated aerobe and anaerobe, respectively. Although there was no difference between diets (P > .10), these two organisms occurred most frequently in cows on the protein deficient diet and were associated with clinically severe uterine infections. These data suggest that the amount of crude protein in the diet affects both the incidence and duration of postpartum infections in the bovine uterus.     

Non-specific uterine infection and bovine fertility. I. Infection patterns and endometritis during the first seven weeks post-partum

From a total of 93 dairy cows which were sampled repetitively throughout the non-gravid period, 14 cows developed persistent purulent endometritis, failed to complete uterine involution and were chronically infertile. The remaining 79 cows had completed uterine involution prior to 50 days post-partum. Forty-seven of these cows subsequently proved to be fertile and 32 cows were infertile. Fertility was not influenced by the variable uterine flora or by the endometritis which was found in all the cows within the first two weeks post-partum. Cows which had uterine infection with $\text{Corynebacterium pyogenes}$ subsequent to Day 21 developed severe endometritis and were almost invariably infertile to the first service. Fertility to subsequent services was not necessarily impaired in those cows which eliminated $\text{C. pyogenes}$ sufficiently early to allow complete uterine involution prior to Day 50. Cows with abnormal oestrous cycles were not particularly susceptible to uterine infection.In all the cows the composition of the uterine flora fluctuated constantly throughout the first 7 weeks pp. as a result of spontaneous contamination, clearance and recontamination. Contamination of the uterus by other non-specific bacteria during the 3 to 4 week period which is required for resolution of severe endometritis induced by $\text{C. pyogenes}$ could lead to a false correlation between the endometritis and the bacterial flora as determined by a single sample. It is concluded that the information which is derived from $\text{in vivo}$ sampling of the uterus in clinically normal cows during the first 7 weeks pp. is of little value in predicting subsequent fertility.     

Some observations on Corynebacterium pyogenes infection of the bovine uterus

Throughout the non-gravid period, bacteriological samples and endometrial biopsy specimens were taken repetitively from the uteri of 93 cows in 9 dairy herds. The genital organs of 7 of the 14 cows which developed chronic purulent endometritis or pyometra were examined at slaughter 8 to 9 months after parturition. $\text{C.}$$\text{pyogenes}$ was recovered at least once from 61 (65.6 $\text{per}$$\text{cent.}$) of the cows. The highest rate of infection was found during the second week post-partum. Intrauterine infection with $\text{C.}$$\text{pyogenes}$ invariably induced endometritis. The severity of the endometrial reaction was determined by the duration of the infection but the lesions never progressed to the “gland site mass” lesions and extensive stromal sclerosis which have been described as the “significant lesions” in endometritis.The duration of the infection also determined the effect of $\text{C.}$$\text{pyogenes}$ on fertility. Transient infection during the puerperium did not affect fertility; transient infection at a later period reduced fertility to one service, rarely to a second or third service; persistent infection induced chronic purulent endometritis or pyometra accompanied initially by functional anoestrum and, after some months, by organic anoestrum. The factors which determined the duration of the intrauterine infection with $\text{C.}$$\text{pyogenes}$ were not identified.     

Uterine infections in the postpartum cow: II. Possible synergistic effect of Fusobacteriumnecrophorum and Corynebacteriumpyogenes

Clinical conditions, which were observed in primiparous Angus and Hereford heifers with postpartum uterine infections are reported. Forty-three of sixty-four cows (67%) had uterine infections. $\text{Corynebacterium}$$\text{pyogenes}$ and $\text{Fusobacterium}$$\text{necrophorum}$ were the most frequently isolated aerobe and anaerobe, respectively. Twelve of the sixty-four cows (18.8%) had infections that involved these species. Three of these twelve cows were infected only with $\text{C.}$$\text{pyogenes}$, two were infected only with $\text{F.}$$\text{necrophorum}$, and seven were infected with both organisms. All five of the cows which were infected with either $\text{C.}$$\text{pyogenes}$ or $\text{F.}$$\text{necrophorum}$ showed signs of estrus and four of the five cows conceived by 110 days postpartum. The single cow that did not conceive was infected with $\text{C.}$$\text{pyogenes}$. Three of the seven cows which were infected with both organisms showed signs of estrus and none of the seven cows conceived by 110 days postpartum. In addition, when only $\text{C.}$$\text{pyogenes}$ or $\text{F.}$$\text{necrophorum}$ was isolated from the uterus, cows had either mild or no clinical signs of infection. In contrast, the seven cows which were infected with both organisms had severe clinical signs of infection that included excessive vulvar discharge, uterine abscesses and pelvic adhesions. These observations suggested that a pathogenic synergism between $\text{C.}$$\text{pyogenes}$ and $\text{F.}$$\text{necrophorum}$ might have caused the increased severity of postpartum uterine infections, and the subsequent detrimental effect on return to estrus and conception.     

Investigations into the potential for embryo transfer from Brucellaabortus infected cows without transmission of infection

Thirty-six attempts were made to isolate $\text{Brucella}$$\text{abortus}$ from the uterine flushings of culture positive and serologic reactor cows. Sixteen of these attempts were made after cows had been programmed for superovulation and a simultaneous attempt was made to recover eggs. Udder secretion samples for culture and blood for serology were collected at the time of the flushing procedure. In addition, a field isolate of $\text{Brucella}$$\text{abortus}$ suspended in three different solutions (one commonly used for nonsurgical embryo retrieval) was quantitated at various intervals up to 24 hours.Brucellae were not cultured from any of the uterine flushings although it was demonstrated that the organisms would remain viable in the media used for up to 24 hours. Udder secretions contained brucella at the time of flushing in 17 of the 36 attempts. Results indicated that transfer from infected donors might be achieved without transfer of infection. It is cautioned that final evidence of success would have to come after recipients had undergone serologic and cultural surveillance through their gestation period.     

Comparison of invivo and invitro uterine contractility in the ewe

Uterine contractions were observed $\text{in}$$\text{vivo}$ by laparotomy and exposure of the uterus. Ten hours after the beginning of estrus, an average of 39 contractions per 10 min originated in the posterior ends of the uterine horns and moved toward the oviducts, while an average of, 13 contractions originated in the anterior ends of the horns and moved toward the cervix. Two days later (58 hr after the beginning of estrus), the contractions had changed in origin and direction; only 6 contractions originated in the posterior ends of the horns and moved anteriorly, while 39 originated in the anterior ends and moved posteriorly.Experiments were done to determine whether the change in origin of contractions $\text{in}$$\text{vivo}$ was reflected in the contractility of strips of myometrium in a tissue bath. The number and amplitude of contractions were recorded from strips of circular and of longitudinal myometrium taken from the posterior and anterior ends of the uterine horns at 10 and 58 hr after the beginning of estrus. The myometrial strips contracted approximately 3 to 4 times per minute regardless of the time after the beginning of estrus, the end of the uterine horn from which the tissue was taken, or whether the contracting muscle was circular or longitudinal. Thus, the physiological mechanisms that controlled the number and origin of uterine contractions $\text{in}$$\text{vivo}$ did not maintain that control over myometrial tissue $\text{in}$$\text{vitro}$.     

Studies of bovine genital tracts: Mycoplasma isolations from dairy cows

Mycoplasma was isolated from the genital tracts of 8 of 96 culled dairy cows. Procedures were used to reduce the possibility of uterine contamination by vaginal fluids. The mycoplasma isolates were identified by the fluorescent antibody technique as: $\text{Mycoplasma bovigenitalium}$ (4), $\text{M. canadense}$ (1), an untyped bovine pathogen from the mammary gland designed as ST-6 (2), and an isolate that could not be identified with the labeled antibodies used in this study. All isolations were made from vaginal swabs, except in one case of pyometra where $\text{M. bovigenitalium}$ was isolated concurrently from the uterus and vagina, along with $\text{Pasteurella hemolyticum}$. These results suggest that mycoplasma may be found in the cervico-vaginal flora of some cattle but are rarely isolated from the uterine environment.     

Synchronized breeding in cattle using PGF2α and LHRH/FSHRH stimulatory analogs

Two studies were conducted to synchronize breeding in cattle using PGF₂α and LHRH/FSHRH analogs. In the first study, 60 mature lactating Angus cows were assigned at random to 4 treatment groups: saline and saline (SS); 30 mg PGF₂α tham salt + saline (PS); saline + 2 mg D-ala⁶-des-GlyNH₂¹⁰ LHRH/FSHRH ethylamide (D-ala⁶) (SA); 30 mg PGF₂α tham salt + 2 mg D-ala⁶ (PA). The first letter of the two-letter code for each group always indicates a dual injection at an 11-day interval. PGF₂α or saline was administered intramuscular (im) twice at an 11 day interval. D-ala⁶ or saline was administered 48 hr after PGF₂α treatment. In the SA group, the D-ala⁶ was administered at first signs of estrus, and cows were then artificially inseminated (AI) 24 hr later. All cows in the PS group were inseminated 72 hr after the second PGF₂α injection. In the SS group, cows were inseminated 24 hr after first signs of estrus. An additional 6 mature lactating Angus cows were added equally to the PS and PA groups to evaluate changes in serum LH. The percent calf crops was: SS = 40% (frsol|6/15); PS = 47% ($\text{7}\text{15}$); SA = 47% ($\text{7}\text{15}$); PA = 53% ($\text{8}\text{15}$). In the second study, 51 mature lactating Angus cows and 39 Holstein heifers were assigned at random to 3 treatment groups: saline + saline (SS); 33.4 mg PGF₂α tham salt + saline (PS); 33.4 mg PGF₂α tham salt + 1 mg D-leu⁶-des GlyNH₂¹⁰ LHRH/FSHRH ethylamide (D-leu⁶) (PL). PGF₂α tham salt or saline was administered im twice at an 11 day interval. D-leu⁶ or saline was administered 68 hr following the second PGF₂α treatment. Cows pretreated with PGF₂α were inseminated 80 hr after the second PGF₂α injection. In the SS group, cows were administered saline at the time of natural estrus and were artificially inseminated 12 hr later. Calving percent to the first AI was SS = 70% ($\text{21}\text{30}$); PS = 53% ($\text{16}\text{30}$) and PL = 40% ($\text{12}\text{30}$). An additional 10 mature lactating Angus cows were used to evaluate changes in serum LH. Five of the cows were assigned to the PS treatment and five to the PL treatment. Sequential blood samples were collected to monitor serum LH levels. Using the Chi-square test, there were no significant differences between calving percentages of the control and PGF₂α treated cows in either study. These results indicate that the PGF₂α treatments were successful in timed artificial insemination of cows without detection of estrus. The LHRH/FSHRH analogs did not improve the conception even though they appear to induce a pituitary release of LH simultaneously in all cows within 1 hr of treatment.     

Diagnosis of trichomoniasis in pregnant cows by culture of cervical-vaginal mucus

The objective of this study was to evaluate the effectiveness of Cervical-Vaginal Mucus (CVM) cultures for isolating $\text{Trichomonas fetus}$ from pregnant cows. Cervical-vaginal mucus was cultured from sixty-eight cows averaging 98 days of gestation. $\text{Trichomonas fetus}$ was isolated from 7 of 36 cows in groups exposed to bulls found to be infected at the end of the breeding season. The remaining 32 cows which were bred to bulls found not to be infected at the end of the breeding season were negative. Seven of the cows serviced by infected bulls aborted. Three of these had been positive and 4 negative on culture. The incidence of abortion was determined by examination 81 days after the previous examination and CVM culture. During the same interval there were no abortions in the 32 cows served by non-infected bulls. Culture of CVM identified infected groups of cows which had a high risk for abortion.     

Transfer of cultured bovine embryos

A total of 126 bovine embryos were surgically collected from 16 superovulated donor heifers 5 days after estrus and randomly selected for either immediate transfer to synchronized recipients or $\text{in}$$\text{vitro}$ culture at 37°C for 24 hours and subsequent transfer. Twenty-four of 56 (42.8%) embryos maintained for 24 hours in Ham's F10 medium supplemented with 10% heat treated fetal calf serum (HTFCS) and transferred to 32 recipients produced live calves. Survival of 70 noncultured embryos transferred to 35 recipients was 55.7% (39 calves). The percentages of recipients that were diagnosed pregnant at 42 days with cultured and control embryos were 59.4% ($\text{19}\text{32}$) and 74.3% ($\text{26}\text{35}$), respectively. No statistical difference was observed between the $\text{in}$$\text{vitro}$ cultured and control embryos for viability following transfer to recipient females.In a second study, Day 7 embryos maintained in Ham's F10 medium supplemented with 10% HTFC serum for various culture periods were tested for viability following nonsurgical transfer to recipient females. A total of $\text{1}\text{5}$, $\text{1}\text{3}$ and $\text{0}\text{4}$ embryos cultured for 24, 48 and 72 hours, respectively, resulted in pregnant recipients following transfer.     

Reproductive responses of beef heifers and cows to exogenous progesterone administered in silastic coils,oestradiol benzoate and pregnant mare serum gonadotropin

The aim of this study was to investigate a Progesterone Releasing Intravaginal Device, Oestradiol benzoate and PMSG combined treatment in 81 suckling charolais cows and 56 heifers of various breeds. The former were young primiparous cows aged 2 years and treated at a means of 43 days postpartum. Most of the heifers ($\text{44}\text{56}$) were not cycling and were believed to be prepuberal.In non-cycling females, the treatment induced ovulation in 98.5% of the cows and 78 to 100% of the heifers according to breed. In those females in which ovulation was induced, pregnancy rates determined by rectal palpation were 46.9% for the cows and 66.7% for the heifers. When taking into account all treated females including those with lost Progesterone Releasing Intravaginal Devices (5.8%) and those not ovulating, the pregnancy rates determined by rectal palpation 3 to 5 months after artificial insemination were 40.7% for the cows and 52% for the heifers.     

An attempt to isolate Brucellaabortus from uterine flushings of brucellosis-reactor donor cattle

Two experiments were conducted to test for the recovery of brucella organisms from uterine flushings and harvested embryos of sero-positive embryo donor females. In Experiment I, 16 sero-positive cows were superovulated with FSH treatments and artificially inseminated at 12, 24 and 36 hours following the onset of estrus with brucella-free semen. At 48 hours after the onset of estrus, one half the potential donor females were administered an intrauterine inoculation of 3.3 to 4.6 × 10⁴$\text{Brucella}$$\text{abortus}$ (strain 2308) organisms while the remainder received a control inoculation. In Experiment II, the same 16 cows were similarly administered superovulatory treatments and inseminated following estrus. The uterine inoculation was increased to 1.5 to 2.5 × 10⁸ organisms administered 48 hours following estrus. Samples of recovered flushing medium and homogenized embryo residues were placed into a validated $\text{in}$$\text{vitro}$ culture system to detect the presence of brucella bacteria. Uterine flushings and embryos recovered from 31 females exhibiting estrus following FSH treatments were free from either field strain or the inoculated $\text{B.}$$\text{abortus}$ (strain 2308) contamination. The flushings obtained from a single female, which did not respond with estrus following FSH treatment but was inoculated at appointment, did contain $\text{B.}$$\text{abortus}$ which was identified as the inoculated strain 2308 and not field strain organisms. These results indicate that brucella contamination of flushing media and harvested embryos will not likely be incurred when collecting embryos from sero-positive donor females. These findings offer further encouragement for the use of embryo transplantation as a method to produce brucella-free offspring from infected cows.     

Factors affecting the survival of whole and half-embryos transferred in cattle

We estimated that embryonic loss in cattle was about 30% after direct blastocyst transfer. This loss occurred mostly before and during implantation and was augmented by handling the embryo during deep-freezing or culture $\text{in vitro}$. Pregnancy rate increased with the number of embryos transferred. The establishment of a “dialogue” between the embryo and uterus thus depended on the number and quality of the embryonic cells transferred. The trophoblastic cells gave the signal maintaining the corpus luteum of the recipient cow, but the survival of the transferred embryo depended on the good viability of the cells of the embryonic disc.To limit early embryonic loss, the embryonic signal could be amplified by transferring a trophoblastic vesicle $\text{in utero}$ at the same time as the embryo.     

Metabolites of estradiol-17β in guinea pig uterus late in pregnancy

The metabolism of estradiol-17β by the guinea pig uterus late in pregnancy was studied $\text{in vivo}$ and $\text{in vitro}$.Whole uteri were examined for estrogen metabolites one hour following an intravenous injection of [³H]-estradiol-17β or uterine sections were examined after incubation for one hour at 37°C in medium containing [³H]-estradiol-17β.In both instances uterine tissue metabolized estradiol-17g to five products: estrone, estrone-3-sulfate, 17β-estradiol-3-sulfate, estrone-3-glucuronide and 17β-estradiol-3-glucuronide. Of the total radioactive products 11 – 43% were glucuronides, 17 – 26% were sulfates and 4 – 17% was estrone. These results indicate that the guinea pig uterus actively transforms estradiol-17β into glucuronides and sulfates late in pregnancy.     

The effect of PGF-2 alpha on reproductive performance of naturally bred dairy cows with or without pyometra

Five hundred thirty-four naturally bred Holstein dairy cows from two Colorado dairies were examined $\text{per}$$\text{rectum}$ between 21 and 36 days after calving. Alternate cows in each herd received either 25 mg PGF-2 alpha or no treatment at the time of initial examination. No differences were found in days open or pregnancy rates between groups (P>0.25).Days open in 23 cows with pyometra were 98.7 ± 9.4, and 77.0 ± 2.2 in 493 herdmates without pyometra. The large inequalities in numbers precluded valid statistical comparisons between these groups. No overall difference (P>0.25) in reproductive performance was found in cows with pyometra treated at the initial examination compared to those not treated until two to four weeks after the initial examination. Contributing to the lack of significance were a number of cows with pyometra that had spontaneous cures before treatment was considered. Untreated cows that recovered spontaneously had better (P<0.05) reproductive performance than herdmates that required later treatments to initiate uterine evacuation. No overall advantage in reproductive performance was obtained by the routine treatment of postpartum dairy cows with PGF-2 alpha but treatment of cows with pyometra should not be delayed.     

The effect of exogenous progesterone on plasma LH and milk progesterone concentrations in multiple-suckling post-partum cows

Fourteen Friesian cows each suckling four calves were treated for a 7-day period (a) between days 20–40 post partum with progesterone-releasing intravaginal devices (PRID) containing 2% progesterone (Group 1; n = 5), (b) between days 51–264 post partum with PRIDS containing 2% progesterone (Group 2; n = 6) and (c) between days 29–214 days post partum with PRIDS containing 0% progesterone (Group 3; n = 3). Mean plasma LH concentrations decreased during PRID treatment in Group 2 cows only and pre-ovulatory LH surges were observed in $\text{5}\text{6}$ of these cows between 38 and 84 h after coil removal. All Group 2 cows underwent at least one ovarian cycle following PRID removal. No pre-ovulatory LH surges were observed in either Group 1 or Group 3 cows and only one cow (Group 3) underwent an ovarian cycle after treatment. It is suggested that there is an increase in pituitary responsiveness to the feedback effects of progesterone during the post-partum period.     

Effect of Dermatophiluscongolensis infection on reproductive performance of dairy cattle

The effect of $\text{Dermatophilus}$$\text{congolensis}$ on reproductive performance and milk production of dairy cattle was investigated using a prospective cohort study design. The following results were obtained: the calving to conception interval was 122 vs 104 days (P<0.05) for cows with lesions (cases) and those without lesions (non-cases), respectively; the 180-day pregnancy rate was 70.3% vs 84.3% (P<0.02) for cases and non-cases, respectively; the interval to first service was 69 days for cases and 64 days for non-cases (P<0.05) and the interval from first to second service was 32.7 days for cases and 49.4 days (P<0.01) for non-cases. The prevalence of cows with lesions was 33% ($\text{66}\text{200}$). Lesions were most commonly found on the skin covering the coccygeal and sacral vertebrae and the gluteal muscles. White skin had a greater prevalence of lesions than did black skin (P<0.05).     

Laparoscopic embryo transfer in domestic sheep: A preliminary study

An effective, minor-invasive technique for embryo transfer in sheep was developed using a laparoscopic transabdominal approach. Twelve recipient ewes received embryos either by conventional laparotomy or by laparoscopy. The estrous cycle of recipient ewes was synchronized using a progestagen-impregnated vaginal pessary/pregnant mares' serum gonadotropin treatment regimen. Donor ewes were superovulated with follicle stimulating hormone or human menopausal gonadotropin, bred with a ram of one breed and laparoscopically inseminated $\text{in}$$\text{utero}$ with semen from a different sheep breed. Five to six days after estrus, embryos were transferred laparoscopically into the terminal one-half of the recipient's uterine horn ipsilateral to the ovary with prominent corpus luteum development. Pregnancy was diagnosed by transrectal ultrasonic procedures, and by direct laparoscopic examination of the uterus. Of six laparoscopic transfers, three resulted in single births; one of six laparotomy transfers resulted in a live birth. Breed appearances of the four lambs born indicated that two of the offspring resulted from laparoscopic artificial insemination of the donor ewe. The results demonstrated that laparoscopic transfer of embryos was a rapid and safe procedure, easily applied to an ovine embryo transfer program and with potential for similiar studies in other species.     

Nuclear transfer studies of amoeba proteus after the inhibition of cell division by injection of non-homologous cytoplasm

Following the injection of the post-microsomal supernatant fraction of $\text{Amoeba discoides}$ cytoplasm into $\text{A.proteus}$, cell division is inhibited in at least 90% of the recipient cells. Nuclear transfers were performed to determine the site of inhibition in these injected cells. When nuclei from injected, inhibited cells one day after injection were transferred into new $\text{A.proteus}$ cytoplasms, 62% of the transfers divided. This ability to promote division declined with the length of time between transfer and the original_ injection. However, when nuclei from $\text{A.proteus}$ were transferred into injected, inhibited cytoplasms, only a low number of cells divided, comparable to the number obtained after the injection operation only, namely less than 10%. Thus although many nuclei could recover from inhibition, it was not possible to restore the cytoplasms of inhibited cells by new nuclei.     

Effect of monensin and suckling on the GnRH induced luteinizing hormone surge and the effect of monensin on the postpartum interval in Brangus cows

Twenty-seven fall calving Brangus cows were randomly allotted to one of four treatment groups: nonsuckled monensin (NSM), suckled monensin (SM), nonsuckled control (NSC), and suckled control (SC). Cows were group fed 1.82 kg/hd/day concentrate and Coastal bermuda grass hay $\text{ad}$$\text{libitum}$. Monensin cows received 200 mg monensin/hd/day in the concentrate. At 0800 hr on day 21 postcalving, the calves were separated from the cows. Suckled monensin and SC cows were allowed to suckle their calves for 30 min at 6-hr intervals. Nonsuckled monensin and NSC cows were not suckled. Calves were given free access to the cows after 1400 hr on day 22 postpartum. At 0800 hr on day 22 postpartum, a blood sample was collected. A 100 μg GnRH challenge was administered IM at 0801 hr. Blood samples were collected at 15-min intervals for 6 hr postinjection. Changes in body weight and body condition from day 21 postpartum to the day of first estrus were not different (P>0.10) by dietary treatment. Monensin cows consumed 10.7% less hay than did the control cows. Serum luteinizing hormone (LH) following GnRH was greater (P<0.005) in suckled than nonsuckled cows. Control cows released more (P<0.005) LH in response to GnRH than did the monensin cows. The postpartum interval (to first estrus) for the monensin cows (92.4±14.7 days) was shorter (P<0.025) than the controls (138.5±9.5 days). A greater proportion (P<0.005) of the monensin cows (8 of 14) exhibited estrus by 90 days postpartum compared to the control cows (0 of 13). Monensin and suckling appear to exert independent and agonistic influences on pituitary function in the postpartum beef cow.